Browsing by Subject "North America"
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Item Open Access Ablation Versus Drug Therapy for Atrial Fibrillation in Racial and Ethnic Minorities.(Journal of the American College of Cardiology, 2021-07) Thomas, Kevin L; Al-Khalidi, Hussein R; Silverstein, Adam P; Monahan, Kristi H; Bahnson, Tristram D; Poole, Jeanne E; Mark, Daniel B; Packer, Douglas L; CABANA InvestigatorsBackground
Rhythm control strategies for atrial fibrillation (AF), including catheter ablation, are substantially underused in racial/ethnic minorities in North America.Objectives
This study sought to describe outcomes in the CABANA trial as a function of race/ethnicity.Methods
CABANA randomized 2,204 symptomatic participants with AF to ablation or drug therapy including rate and/or rhythm control drugs. Only participants in North America were included in the present analysis, and participants were subgrouped as racial/ethnic minority or nonminority with the use of National Institutes of Health definitions. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.Results
Of 1,280 participants enrolled in CABANA in North America, 127 (9.9%) were racial and ethnic minorities. Compared with nonminorities, racial and ethnic minorities were younger with median age 65.6 versus 68.5 years, respectively, and had more symptomatic heart failure (37.0% vs 22.0%), hypertension (92.1% vs 76.8%, respectively), and ejection fraction <40% (20.8% vs 7.1%). Racial/ethnic minorities treated with ablation had a 68% relative reduction in the primary endpoint (adjusted hazard ratio [aHR]: 0.32; 95% confidence interval [CI]: 0.13-0.78) and a 72% relative reduction in all-cause mortality (aHR: 0.28; 95% CI: 0.10-0.79). Primary event rates in racial/ethnic minority and nonminority participants were similar in the ablation arm (4-year Kaplan-Meier event rates 12.3% vs 9.9%); however, racial and ethnic minorities randomized to drug therapy had a much higher event rate than nonminority participants (27.4% vs. 9.4%).Conclusion
Among racial or ethnic minorities enrolled in the North American CABANA cohort, catheter ablation significantly improved major clinical outcomes compared with drug therapy. These benefits, which were not seen in nonminority participants, appear to be due to worse outcomes with drug therapy. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial [CABANA]; NCT00911508).Item Open Access Acute Adverse Events After Spinal Cord Injury and Their Relationship to Long-term Neurologic and Functional Outcomes: Analysis From the North American Clinical Trials Network for Spinal Cord Injury.(Critical care medicine, 2019-11) Jiang, Fan; Jaja, Blessing NR; Kurpad, Shekar N; Badhiwala, Jetan H; Aarabi, Bizhan; Grossman, Robert G; Harrop, James S; Guest, Jim D; Schär, Ralph T; Shaffrey, Chris I; Boakye, Max; Toups, Elizabeth G; Wilson, Jefferson R; Fehlings, Michael G; North American Clinical Trials Network CollaboratorsObjectives
There are few contemporary, prospective multicenter series on the spectrum of acute adverse events and their relationship to long-term outcomes after traumatic spinal cord injury. The goal of this study is to assess the prevalence of adverse events after traumatic spinal cord injury and to evaluate the effects on long-term clinical outcome.Design
Multicenter prospective registry.Setting
Consortium of 11 university-affiliated medical centers in the North American Clinical Trials Network.Patients
Eight-hundred one spinal cord injury patients enrolled by participating centers.Interventions
Appropriate spinal cord injury treatment at individual centers.Measurements and main results
A total of 2,303 adverse events were recorded for 502 patients (63%). Penalized maximum logistic regression models were fitted to estimate the likelihood of neurologic recovery (ASIA Impairment Scale improvement ≥ 1 grade point) and functional outcomes in subjects who developed adverse events at 6 months postinjury. After accounting for potential confounders, the group that developed adverse events showed less neurologic recovery (odds ratio, 0.55; 95% CI, 0.32-0.96) and was more likely to require assisted breathing (odds ratio, 6.55; 95% CI, 1.17-36.67); dependent ambulation (odds ratio, 7.38; 95% CI, 4.35-13.06) and have impaired bladder (odds ratio, 9.63; 95% CI, 5.19-17.87) or bowel function (odds ratio, 7.86; 95% CI, 4.31-14.32) measured using the Spinal Cord Independence Measure subscores.Conclusions
Results from this contemporary series demonstrate that acute adverse events are common and are associated with worsened long-term outcomes after traumatic spinal cord injury.Item Open Access Analyzing Energy Outlooks: Focusing on North America and the United States of America(2012-04-27) Molinari, TerrenceThere are broad ranges of organizations that produce energy forecasts for different purposes. The U.S. Department of Energy produces an International Energy Outlook through their Energy Information Administration (EIA), whose objective is to provide facts for public policy decisions. The International Energy Agency (IEA) produces a World Energy Outlook to ensure their members maintain energy security and have research to achieve clean, cheap and affordable energy sources. Furthermore, various public companies produce outlooks, such as BP and ExxonMobil, which both do so in an effort to promote discussion around energy issues. Assumptions made about policy, technology, economic development, and demographics strongly affect the different models used in each survey. The objectives of analyzing these outlooks together are to determine how and where they differ, and to explain these differences quantitatively and qualitatively. The most influencing factor, for all the energy types, was the scenario assumption, namely policy and technology assumptions. Projections that differ the most, or were most similar, can be generally explained by understanding the policy and technology assumptions behind each survey. The EIA provides projections for consumption in production for the status quo, in regards to policy and technology innovation. The IEA used policies that were announced and implements them cautiously. They also take into account foreseeable technology advances. BP and ExxonMobil incorporate the most likely or most practical policy and technology advances in their projections. Evaluating the differences and the goals of each forecast will allow for a non-biased, well-rounded understanding and discussion of energy projections from these different organizations. Each organization believes it is important to continue the discussion of energy markets world-wide. Each outlook has differences that impede discussion, thus this study suggests a standardization of energy forecasts in order to not only enable discussion, but also truly expand discussion from not just people in the know, but to the common folk.Item Open Access Anterior versus posterior surgical approaches to treat cervical spondylotic myelopathy: outcomes of the prospective multicenter AOSpine North America CSM study in 264 patients.(Spine, 2013-12) Fehlings, Michael G; Barry, Sean; Kopjar, Branko; Yoon, Sangwook Tim; Arnold, Paul; Massicotte, Eric M; Vaccaro, Alexander; Brodke, Darrel S; Shaffrey, Christopher; Smith, Justin S; Woodard, Eric; Banco, Robert J; Chapman, Jens; Janssen, Michael; Bono, Christopher; Sasso, Rick; Dekutoski, Mark; Gokaslan, Ziya LStudy design
A prospective observational multicenter study.Objective
To help solve the debate regarding whether the anterior or posterior surgical approach is optimal for patients with cervical spondylotic myelopathy (CSM).Summary of background data
The optimal surgical approach to treat CSM remains debated with varying opinions favoring anterior versus posterior surgical approaches. We present an analysis of a prospective observational multicenter study examining outcomes of surgical treatment for CSM.Methods
A total of 278 subjects from 12 sites in North America received anterior/posterior or combined surgery at the discretion of the surgeon. This study focused on subjects who had either anterior or posterior surgery (n = 264, follow-up rate, 87%). Outcome measures included the modified Japanese Orthopedic Assessment scale, the Nurick scale, the Neck Disability Index, and the Short-Form 36 (SF-36) Health Survey version 2 Physical and Mental Component Scores.Results
One hundred and sixty-nine patients were treated anteriorly and 95 underwent posterior surgery. Anterior surgical cases were younger and had less severe myelopathy as assessed by mJOA and Nurick scores. There were no baseline differences in Neck Disability Index or SF-36 between the anterior and posterior cases. Improvement in the mJOA was significantly lower in the anterior group than posterior group (2.47 vs. 3.62, respectively, P < 0.01), although the groups started at different levels of baseline impairment. The extent of improvement in the Nurick Scale, Neck Disability Index, SF-36 version 2 Physical Component Score, and SF-36 version 2 Mental Component Score did not differ between the groups.Conclusion
Patients with CSM show significant improvements in several health-related outcome measures with either anterior or posterior surgery. Importantly, patients treated with anterior techniques were younger, with less severe impairment and more focal pathology. We demonstrate for the first time that, when patient and disease factors are controlled for, anterior and posterior surgical techniques have equivalent efficacy in the treatment of CSM.Level of evidence
3.Item Open Access Describing the diversity of community supported fishery programs in North America(Marine Policy, 2016-04-01) Bolton, AE; Dubik, BA; Stoll, JS; Basurto, X© 2016 Elsevier Ltd. This research investigates organizational diversity within Community Supported Fisheries (CSFs) in North America. Generally understood as the direct marketing of seafood through pre-arranged deliveries, CSFs have increased in number and geographic distribution since their origin in 2007. Despite, or because of, this rapid growth, fundamental questions remain unanswered about what organizational structures and business practices currently constitute the term 'CSF'. This research draws on interview data from 22 CSFs to highlight the diversity within the CSF movement and inform ongoing debates about appropriate paths for their continued growth. Interview data is used to describe key areas of convergence and divergence among the goals, business practices, and structures of CSFs. Three general types of CSF are identified based on this analysis: harvester focused, consumer focused and species focused. Each type is described through a short illustrative case study. Overall results indicate that the term 'CSF' does not currently refer to a specific structure or type of organization, but rather an approach to seafood marketing used by a variety of organizations with broadly similar production philosophies centered on engaging and informing consumers around traceable, domestically sourced seafood. Acknowledgment of CSFs as diverse and socially embedded organizations is necessary to understanding their potential benefits.Item Open Access Ecological restoration of rich fens in Europe and North America: from trial and error to an evidence-based approach.(Biol Rev Camb Philos Soc, 2015-02) Lamers, Leon PM; Vile, Melanie A; Grootjans, Ab P; Acreman, Mike C; van Diggelen, Rudy; Evans, Martin G; Richardson, Curtis J; Rochefort, Line; Kooijman, Annemieke M; Roelofs, Jan GM; Smolders, Alfons JPFens represent a large array of ecosystem services, including the highest biodiversity found among wetlands, hydrological services, water purification and carbon sequestration. Land-use change and drainage has severely damaged or annihilated these services in many parts of North America and Europe; restoration plans are urgently needed at the landscape level. We review the major constraints on the restoration of rich fens and fen water bodies in agricultural areas in Europe and disturbed landscapes in North America: (i) habitat quality problems: drought, eutrophication, acidification, and toxicity, and (ii) recolonization problems: species pools, ecosystem fragmentation and connectivity, genetic variability, and invasive species; and here provide possible solutions. We discuss both positive and negative consequences of restoration measures, and their causes. The restoration of wetland ecosystem functioning and services has, for a long time, been based on a trial-and-error approach. By presenting research and practice on the restoration of rich fen ecosystems within agricultural areas, we demonstrate the importance of biogeochemical and ecological knowledge at different spatial scales for the management and restoration of biodiversity, water quality, carbon sequestration and other ecosystem services, especially in a changing climate. We define target processes that enable scientists, nature managers, water managers and policy makers to choose between different measures and to predict restoration prospects for different types of deteriorated fens and their starting conditions.Item Open Access Effect of type II odontoid fracture nonunion on outcome among elderly patients treated without surgery: based on the AOSpine North America geriatric odontoid fracture study.(Spine, 2013-12) Smith, Justin S; Kepler, Christopher K; Kopjar, Branko; Harrop, James S; Arnold, Paul; Chapman, Jens R; Fehlings, Michael G; Vaccaro, Alexander R; Shaffrey, Christopher IStudy design
Subgroup analysis of a prospective multicenter study.Objective
Outcome analysis of nonoperatively treated elderly patients with type II odontoid fractures, including assessment of consequence of a fracture nonunion.Summary of background data
Odontoid fractures are among the most common fractures in the elderly, and controversy exists regarding treatment.Methods
Subgroup analysis of a prospective multicenter study of elderly patients (≥65 yr) with type II odontoid fracture. Neck Disability Index and Short-Form 36 (SF-36) version 2 were collected at baseline and 6 and 12 months. Fifty-eight (36.5%) of the 159 patients were treated nonoperatively.Results
Of the 58 patients initially treated nonoperatively, 8 died within 90 days and were excluded. Of the remaining 50 patients, 11 (22.0%) developed nonunion, with 7 (63.6%) requiring surgery. Four of the 39 (10.3%) patients classified as having "successful union" required surgery due to late fracture displacement. Thus, 15 (30.0%) patients developed primary or secondary nonunion and 11 (22.0%) required surgery. The overall 12-month mortality was 14.0% (nonunion = 2, union = 5; P= 0.6407). For union and nonunion groups, Neck Disability Index and SF-36 version 2 declined significantly at 12 months compared with preinjury values (P< 0.05), except for SF-36 version 2 Physical Functioning (P= 0.1370). There were no significant differences in outcome parameters based on union status at 12 months (P> 0.05); however, it is important to emphasize that the 12-month outcomes for the nonunion patients reflect the status of the patient after delayed surgical treatment in the majority of these cases.Conclusion
Nonoperative treatment for type II odontoid fracture in the elderly has high rates of nonunion and mortality. Patients with nonunion did not report worse outcomes compared with those who achieved union at 12 months; however, the majority of patients with nonunion required delayed surgical treatment. These findings may prove useful for patients who are not surgical candidates or elect for nonoperative treatment.Level of evidence
2.Item Open Access Efficacy and safety of surgical decompression in patients with cervical spondylotic myelopathy: results of the AOSpine North America prospective multi-center study.(The Journal of bone and joint surgery. American volume, 2013-09) Fehlings, Michael G; Wilson, Jefferson R; Kopjar, Branko; Yoon, Sangwook Tim; Arnold, Paul M; Massicotte, Eric M; Vaccaro, Alexander R; Brodke, Darrel S; Shaffrey, Christopher I; Smith, Justin S; Woodard, Eric J; Banco, Robert J; Chapman, Jens R; Janssen, Michael E; Bono, Christopher M; Sasso, Rick C; Dekutoski, Mark B; Gokaslan, Ziya LBackground
Cervical spondylotic myelopathy is the leading cause of spinal cord dysfunction worldwide. The objective of this study was to evaluate the impact of surgical decompression on functional, quality-of-life, and disability outcomes at one year after surgery in a large cohort of patients with this condition.Methods
Adult patients with symptomatic cervical spondylotic myelopathy and magnetic resonance imaging evidence of spinal cord compression were enrolled at twelve North American centers from 2005 to 2007. At enrollment, the myelopathy was categorized as mild (modified Japanese Orthopaedic Association [mJOA] score ≥ 15), moderate (mJOA = 12 to 14), or severe (mJOA < 12). Patients were followed prospectively for one year, at which point the outcomes of interest included the mJOA score, Nurick grade, Neck Disability Index (NDI), and Short Form-36 version 2 (SF-36v2). All outcomes at one year were compared with the preoperative values with use of univariate paired statistics. Outcomes were also compared among the severity classes with use of one-way analysis of variance. Finally, a multivariate analysis that adjusted for baseline differences among the severity groups was performed. Treatment-related complication data were collected and the overall complication rate was calculated.Results
Eighty-five (30.6%) of the 278 enrolled patients had mild cervical spondylotic myelopathy, 110 (39.6%) had moderate disease, and 83 (29.9%) had severe disease preoperatively. One-year follow-up data were available for 222 (85.4%) of 260 patients. There was a significant improvement from baseline to one year postoperatively (p < 0.05) in the mJOA score, Nurick grade, NDI score, and all SF-36v2 health dimensions (including the mental and physical health composite scores) except general health. With the exception of the change in the mJOA, the degree of improvement did not depend on the severity of the preoperative symptoms. These results remained unchanged after adjusting for relevant confounders in the multivariate analysis. Fifty-two patients experienced complications (prevalence, 18.7%), with no significant differences among the severity groups.Conclusions
Surgical decompression for the treatment of cervical spondylotic myelopathy was associated with improvement in functional, disability-related, and quality-of-life outcomes at one year of follow-up for all disease severity categories. Furthermore, complication rates observed in the study were commensurate with those in previously reported cervical spondylotic myelopathy series.Item Open Access Ethnic Variations in Radiographic Parameters and SRS-22 Scores in Adult Spinal Deformity: A Comparison Between North American and Japanese Patients Above 50 Years of Age With Minimum 2-Year Follow-up.(Clinical spine surgery, 2018-06) Hosogane, Naobumi; Ames, Christopher; Matsumoto, Morio; Yagi, Mitsuru; Matsuyama, Yukihiro; Taneichi, Hiroshi; Yamato, Yu; Takeuchi, Daisaku; Schwab, Frank; Shaffrey, Christopher; Smith, Justin S; Bess, Shay; Lafage, Virginie; International Spine Study GroupStudy design
Retrospective review of North American and Japanese adult spinal deformity (ASD) database.Objective
To investigate the ethnical differences in radiographic parameters and Scoliosis Research Society (SRS)-22 between North American and Japanese ASD.Summary of background data
Previous comparison study between North American and Japanese ASD patients has revealed Japanese patients had marked pelvic tilt deformity and had lower Oswestry Disability Index scores corresponding to established thresholds of radiographic deformity. However, the subjects of the previous study included relatively younger ASD patients (above 18 y) of idiopathic origin.Materials and methods
Total 282 ASD patients older than 50 years, 211 patients from North America (United States) and 71 patients from Japan (JP), with minimum 2-year follow-up postoperatively were included in the study. Radiologic parameters were compared at the baseline and at 2-year follow-up. SRS-22 score was used for the comparison of clinical outcome.Results
At baseline, Japan showed significantly worse sagittal alignment such as smaller lumbar lordosis (LL), larger pelvic incidence (PI), and larger sagittal vertical axis than United States. However, Japan had significantly fewer levels fused than United States (US, 12.66±4.6; JP, 8.49±2.7). At 2 years after the surgery, Japan still had significantly worse residual sagittal deformity. Comparison of SRS-22 scores revealed Japan had better pain but worse functional domain scores at baseline which improved to comparable levels to the United States at 2 years. Self-image and mental health scores in Japan were significantly worse both at baseline and at 2 years. Analysis of factors affecting SRS-22 satisfaction score at 2 years revealed that previous spinal fusion surgery in the United States and LL, PI-LL, and sagittal vertical axis at 2 years in Japan had significant correlation.Conclusions
These similarities and discrepancies may be influenced by the cultural or lifestyle differences between both nations and should be considered when interpreting the results of ASD studies among different ethnicities.Item Open Access Evidence for reciprocal origins in Polypodium hesperium (Polypodiaceae): a fern model system for investigating how multiple origins shape allopolyploid genomes.(American journal of botany, 2014-09-17) Sigel, EM; Windham, MD; Pryer, KM•Many polyploid species are composed of distinct lineages originating from multiple, independent polyploidization events. In the case of allopolyploids, reciprocal crosses between the same progenitor species can yield lineages with different uniparentally inherited plastid genomes. While likely common, there are few well-documented examples of such reciprocal origins. Here we examine a case of reciprocal allopolyploid origins in the fern Polypodium hesperium and present it as a natural model system for investigating the evolutionary potential of duplicated genomes.•Using a combination of uniparentally inherited plastid and biparentally inherited nuclear sequence data, we investigated the distributions and relative ages of reciprocally formed lineages in Polypodium hesperium, an allotetraploid fern that is broadly distributed in western North America.•The reciprocally derived plastid haplotypes of Polypodium hesperium are allopatric, with populations north and south of 42°N latitude having different plastid genomes. Incorporating biogeographic information and previously estimated ages for the diversification of its diploid progenitors, we estimate middle to late Pleistocene origins of P. hesperium.•Several features of Polypodium hesperium make it a particularly promising system for investigating the evolutionary consequences of allopolyploidy. These include reciprocally derived lineages with disjunct geographic distributions, recent time of origin, and extant diploid progenitors.Item Open Access Focal therapy in prostate cancer-report from a consensus panel.(J Endourol, 2010-05) de la Rosette, J; Ahmed, H; Barentsz, J; Johansen, T Bjerklund; Brausi, M; Emberton, M; Frauscher, F; Greene, D; Harisinghani, M; Haustermans, K; Heidenreich, A; Kovacs, G; Mason, M; Montironi, R; Mouraviev, V; de Reijke, T; Taneja, S; Thuroff, S; Tombal, B; Trachtenberg, J; Wijkstra, H; Polascik, TPURPOSE: To establish a consensus in relation to case selection, conduct of therapy, and outcomes that are associated with focal therapy for men with localized prostate cancer. MATERIAL AND METHODS: Urologic surgeons, radiation oncologists, radiologists, and histopathologists from North America and Europe participated in a consensus workshop on focal therapy for prostate cancer. The consensus process was face to face within a structured meeting, in which pertinent clinical issues were raised, discussed, and agreement sought. Where no agreement was possible, this was acknowledged, and the nature of the disagreement noted. RESULTS: Candidates for focal treatment should have unilateral low- to intermediate-risk disease with clinical stageItem Open Access Identifying Barriers and Practical Solutions to Conducting Site-Based Research in North America: Exploring Acute Heart Failure Trials As a Case Study.(Heart Fail Clin, 2015-10) Ambrosy, Andrew P; Mentz, Robert J; Krishnamoorthy, Arun; Greene, Stephen J; Severance, Harry WAlthough the prognosis of ambulatory heart failure (HF) has improved dramatically there have been few advances in the management of acute HF (AHF). Despite regional differences in patient characteristics, background therapy, and event rates, AHF clinical trial enrollment has transitioned from North America and Western Europe to Eastern Europe, South America, and Asia-Pacific where regulatory burden and cost of conducting research may be less prohibitive. It is unclear if the results of clinical trials conducted outside of North America are generalizable to US patient populations. This article uses AHF as a paradigm and identifies barriers and practical solutions to successfully conducting site-based research in North America.Item Open Access International variation in characteristics and clinical outcomes of patients with type 2 diabetes and heart failure: Insights from TECOS.(American heart journal, 2019-12) Bhatt, Ankeet S; Luo, Nancy; Solomon, Nicole; Pagidipati, Neha J; Ambrosio, Giuseppe; Green, Jennifer B; McGuire, Darren K; Standl, Eberhard; Cornel, Jan H; Halvorsen, Sigrun; Lopes, Renato D; White, Harvey D; Holman, Rury R; Peterson, Eric D; Mentz, Robert J; TECOS Study GroupInternational differences in management/outcomes among patients with type 2 diabetes and heart failure (HF) are not well characterized. We sought to evaluate geographic variation in treatment and outcomes among these patients. METHODS AND RESULTS: Among 14,671 participants in the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS), those with HF at baseline and a documented ejection fraction (EF) (N = 1591; 10.8%) were categorized by enrollment region (North America, Latin America, Western Europe, Eastern Europe, and Asia Pacific). Cox models were used to examine the association between geographic region and the primary outcome of all-cause mortality (ACM) or hospitalization for HF (hHF) in addition to ACM alone. Analyses were stratified by those with EF <40% or EF ≥40%. The majority of participants with HF were enrolled in Eastern Europe (53%). Overall, 1,267 (79.6%) had EF ≥40%. β-Blocker (83%) and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (86%) use was high across all regions in patients with EF <40%. During a median follow-up of 2.9 years, Eastern European participants had lower rates of ACM/hHF compared with North Americans (adjusted hazard ratio: 0.45; 95% CI: 0.32-0.64). These differences were seen only in the EF ≥40% subgroup and not the EF <40% subgroup. ACM was similar among Eastern European and North American participants (adjusted hazard ratio: 0.79; 95% CI: 0.44-1.45). CONCLUSIONS: Significant variation exists in the clinical features and outcomes of HF patients across regions in TECOS. Patients from Eastern Europe had lower risk-adjusted ACM/hHF than those in North America, driven by those with EF ≥40%. These data may inform the design of future international trials.Item Open Access Modifying the ‘pulse-reserve’ paradigm for deserts of North America: precipitation pulses, soil water and plant responses(Oecologia, 2004) REYNOLDS; James, F; Kemp, PR; Ogle, K; Fernández, RJThe 'pulse-reserve' conceptual model--arguably one of the most-cited paradigms in aridland ecology--depicts a simple, direct relationship between rainfall, which triggers pulses of plant growth, and reserves of carbon and energy. While the heuristics of 'pulses', 'triggers' and 'reserves' are intuitive and thus appealing, the value of the paradigm is limited, both as a conceptual model of how pulsed water inputs are translated into primary production and as a framework for developing quantitative models. To overcome these limitations, we propose a revision of the pulse-reserve model that emphasizes the following: (1) what explicitly constitutes a biologically significant 'rainfall pulse', (2) how do rainfall pulses translate into usable 'soil moisture pulses', and (3) how are soil moisture pulses differentially utilized by various plant functional types (FTs) in terms of growth? We explore these questions using the patch arid lands simulation (PALS) model for sites in the Mojave, Sonoran, and Chihuahuan deserts of North America. Our analyses indicate that rainfall variability is best understood in terms of sequences of rainfall events that produce biologically-significant 'pulses' of soil moisture recharge, as opposed to individual rain events. In the desert regions investigated, biologically significant pulses of soil moisture occur in either winter (October-March) or summer (July-September), as determined by the period of activity of the plant FTs. Nevertheless, it is difficult to make generalizations regarding specific growth responses to moisture pulses, because of the strong effects of and interactions between precipitation, antecedent soil moisture, and plant FT responses, all of which vary among deserts and seasons. Our results further suggest that, in most soil types and in most seasons, there is little separation of soil water with depth. Thus, coexistence of plant FTs in a single patch as examined in this PALS study is likely to be fostered by factors that promote: (1) separation of water use over time (seasonal differences in growth), (2) relative differences in the utilization of water in the upper soil layers, or (3) separation in the responses of plant FTs as a function of preceding conditions, i.e., the physiological and morphological readiness of the plant for water-uptake and growth. Finally, the high seasonal and annual variability in soil water recharge and plant growth, which result from the complex interactions that occur as a result of rainfall variability, antecedent soil moisture conditions, nutrient availability, and plant FT composition and cover, call into question the use of simplified vegetation models in forecasting potential impacts of climate change in the arid zones in North America.Item Open Access Perioperative and delayed complications associated with the surgical treatment of cervical spondylotic myelopathy based on 302 patients from the AOSpine North America Cervical Spondylotic Myelopathy Study.(Journal of neurosurgery. Spine, 2012-05) Fehlings, Michael G; Smith, Justin S; Kopjar, Branko; Arnold, Paul M; Yoon, S Tim; Vaccaro, Alexander R; Brodke, Darrel S; Janssen, Michael E; Chapman, Jens R; Sasso, Rick C; Woodard, Eric J; Banco, Robert J; Massicotte, Eric M; Dekutoski, Mark B; Gokaslan, Ziya L; Bono, Christopher M; Shaffrey, Christopher IObject
Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM.Methods
Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors.Results
The study enrolled 302 patients (mean age 57 years, range 29-86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002-1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002-1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015-1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626-17.256, p = 0.006).Conclusions
For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.Item Open Access Risk factors for clonal hematopoiesis of indeterminate potential in people with HIV: a report from the REPRIEVE trial.(Blood advances, 2024-02) Bhattacharya, Romit; Uddin, Md Mesbah; Patel, Aniruddh P; Niroula, Abhishek; Finneran, Phoebe; Bernardo, Rachel; Fitch, Kathleen V; Lu, Michael T; Bloomfield, Gerald S; Malvestutto, Carlos; Aberg, Judy A; Fichtenbaum, Carl J; Hornsby, Whitney; Ribaudo, Heather J; Libby, Peter; Ebert, Benjamin L; Zanni, Markella V; Douglas, Pamela S; Grinspoon, Steven K; Natarajan, PradeepAbstract
Clonal hematopoiesis of indeterminate potential (CHIP), the clonal expansion of myeloid cells with leukemogenic mutations, results in increased coronary artery disease (CAD) risk. CHIP is more prevalent among people with HIV (PWH), but the risk factors are unknown. CHIP was identified among PWH in REPRIEVE (Randomized Trial to Prevent Vascular Events in HIV) using whole-exome sequencing. Logistic regression was used to associate sociodemographic factors and HIV-specific factors with CHIP adjusting for age, sex, and smoking status. In the studied global cohort of 4486 PWH, mean age was 49.9 (standard deviation [SD], 6.4) years; 1650 (36.8%) were female; and 3418 (76.2%) were non-White. CHIP was identified in 223 of 4486 (4.97%) and in 38 of 373 (10.2%) among those aged ≥60 years. Age (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.05-1.09; P < .0001) and smoking (OR, 1.37; 95% CI, 1.14-1.66; P < .001) associated with increased odds of CHIP. Globally, participants outside of North America had lower odds of CHIP including sub-Saharan Africa (OR, 0.57; 95% CI, 0.4-0.81; P = .0019), South Asia (OR, 0.45; 95% CI, 0.23-0.80; P = .01), and Latin America/Caribbean (OR, 0.56; 95% CI, 0.34-0.87; P = .014). Hispanic/Latino ethnicity (OR, 0.38; 95% CI, 0.23-0.54; P = .002) associated with significantly lower odds of CHIP. Among HIV-specific factors, CD4 nadir <50 cells/mm3 associated with a 1.9-fold (95%CI, 1.21-3.05; P = .006) increased odds of CHIP, with the effect being significantly stronger among individuals with short duration of antiretroviral therapy (ART; OR, 4.15; 95% CI, 1.51-11.1; P = .005) (Pinteraction= .0492). Among PWH at low-to-moderate CAD risk on stable ART, smoking, CD4 nadir, North American origin, and non-Hispanic ethnicity associated with increased odds of CHIP. This trial was registered at www.ClinicalTrials.gov as NCT02344290.Item Open Access The AOSpine North America Geriatric Odontoid Fracture Mortality Study: a retrospective review of mortality outcomes for operative versus nonoperative treatment of 322 patients with long-term follow-up.(Spine, 2013-06) Chapman, Jens; Smith, Justin S; Kopjar, Branko; Vaccaro, Alexander R; Arnold, Paul; Shaffrey, Christopher I; Fehlings, Michael GSTUDY DESIGN: Retrospective, multicenter cohort study. OBJECTIVE: Assess for differences in short- and long-term mortality between operative and nonoperative treatment for elderly patients with type II odontoid fractures. SUMMARY OF BACKGROUND DATA: There is controversy regarding whether operative or nonoperative management is the best treatment for elderly patients with type II odontoid fractures. METHODS: This is a retrospective study of consecutive patients aged 65 years or older with type II odontoid fracture from 3 level I trauma centers from 2003-2009. Demographics, comorbidities, and treatment were abstracted from medical records. Mortality outcomes were obtained from medical records and a public database. Hazard ratios (HRs) and 95% confidence intervals (CI) were calculated. RESULTS: A total of 322 patients were included (mean age, 81.8 yr; range, 65.0-101.5 yr). Compared with patients treated nonoperatively (n = 157), patients treated operatively (n = 165) were slightly younger (80.4 vs. 83.2 yr, P = 0.0014), had a longer hospital (15.0 vs. 7.4 d, P < 0.001) and intensive care unit (1.5 vs. 1.1 d, P = 0.008) stay, and were more likely to receive a feeding tube (18% vs. 5%, P = 0.0003). Operative and nonoperative treatment groups had similar sex distribution (P = 0.94) and Charlson comorbidity index (P = 0.11). Within 30 days of presentation, 14% of patients died, and at maximal follow-up (average = 2.05 yr; range = 0 d-7.02 yr), 44% had died. On multivariate analysis, nonoperative treatment was associated with higher 30-day mortality (HR = 3.00, 95% CI = 1.51-5.94, P = 0.0017), after adjusting for age (HR = 1.10, 95% CI = 1.05-1.14; P < 0.0001), male sex (P = 0.69), and Charlson comorbidity index (P = 0.16). At maximal follow-up, there was a trend toward higher mortality associated with nonoperative treatment (HR = 1.35, 95% CI = 0.97-1.89, P = 0.079), after adjusting for age (HR = 1.07, 95% CI = 1.05-1.10; P < 0.0001), male sex (HR = 1.55, 95% CI = 1.10-2.16; P = 0.012), and Charlson comorbidity index (HR = 1.28, 95% CI = 1.16-1.40; P < 0.0001). CONCLUSION: Surgical treatment of type II odontoid fracture in this elderly population did not negatively impact survival, even after adjusting for age, sex, and comorbidities. The data suggest a significant 30-day survival advantage and a trend toward improved longer-term survival for operatively treated over nonoperatively treated patients. LEVEL OF EVIDENCE: 4.Item Open Access The National Neurosurgery Quality and Outcomes Database (N2QOD): a collaborative North American outcomes registry to advance value-based spine care.(Spine, 2014-10) Asher, Anthony L; Speroff, Ted; Dittus, Robert S; Parker, Scott L; Davies, Jason M; Selden, Nathan; Nian, Hui; Glassman, Steven; Mummaneni, Praveen; Shaffrey, Christopher; Watridge, Clarence; Cheng, Joseph S; McGirt, Mathew JStudy design
National Prospective Observational Registry.Objective
Describe our preliminary experience with the National Neurosurgery Quality and Outcomes Database (NQOD), a national collaborative registry of quality and outcomes reporting after low back surgery.Summary of background data
All major health care stakeholders are now requiring objective data regarding the value of medical services. Surgical therapies for spinal disorders have faced particular scrutiny in recent value-based discussions, in large part due to the dramatic growth in the cost and application of these procedures. Reliable data are fundamental to understanding the value of delivered health care. Clinical registries are increasingly used to provide such data.Methods
The NQOD is a prospective observational registry designed to establish risk-adjusted expected morbidity and 1-year outcomes for the most common lumbar surgical procedures performed by spine surgeons; provide practice groups and hospitals immediate infrastructure for analyzing their 30-day morbidity and mortality and 3- and 12-month quality data in real-time; generate surgeon-, practice-, and specialty-specific quality and efficacy data; and generate nationwide quality and effectiveness data on specific surgical treatments.Results
In its first 2 years of operation, the NQOD has proven to be a robust data collection platform that has helped demonstrate the objective quality of surgical interventions for medically refractory disorders of the lumbar spine. Lumbar spine surgery was found to be safe and effective at the group mean level in routine practice. Subgroups of patients did not report improvement using validated outcome measures. Substantial variation in treatment response was observed among individual patients.Conclusion
The NQOD is now positioned to determine the combined contribution of patient variables to specific clinical and patient-reported outcomes. These analyses will ultimately facilitate shared decision making and encourage efficient allocation of health care resources, thus significantly advancing the value paradigm in spine care.Level of evidence
3.